Cholate photoacid generators and photoresists comprising same

ABSTRACT

New photoacid generator compounds (“PAGs”) are provided that comprise a cholate moiety and photoresist compositions that comprise such PAG compounds.

This application claims the benefit of priority under 35 U.S.C. §119(e)to U.S. application Ser. No. 12/965,339, filed Dec. 10, 2010, the entirecontents of which application are incorporated herein by reference.

This invention relates to new photoacid generator compounds (“PAGs”)that comprise a cholate moiety and photoresist compositions thatcomprise such PAG compounds.

Photoresists are photosensitive films for transfer of images to asubstrate. They form negative or positive images. After coating aphotoresist on a substrate, the coating is exposed through a patternedphotomask to a source of activating energy such as ultraviolet light toform a latent image in the photoresist coating. The photomask has areasopaque and transparent to activating radiation that define an imagedesired to be transferred to the underlying substrate.

Known photoresists can provide features having resolution and sizesufficient for many existing commercial applications. However for manyother applications, the need exists for new photoresists that canprovide highly resolved images of submicron dimension.

Various attempts have been made to alter the make-up of photoresistcompositions to improve performance of functional properties. Amongother things, a variety of photoactive compounds have been reported foruse in photoresist compositions. See, e.g., U.S. Pat. Nos. 6,664,022 and6,849,374 and U.S. Patent Publication 2009/0061358.

In one aspect, we now provide novel photoacid generator compounds (PAGs)that comprise a cholate moiety for use in either positive-acting ornegative-acting photoresist compositions. Preferably the PAG is an ioniccompound, particularly a sulfonium compound. In the case of suchsulfonium compounds, preferably the cholate group is a moiety of theanionic component of the PAG. For example, in a preferred aspect, thecholate group is a moiety of a fluorinated sulfonate anion compound,particularly where the anion compound comprises an extended saturatedlinker group as discussed below.

As referred to herein, the term “cholate” is inclusive of steroidstructures in general, including C₂₀₋₅₀ hydrocarbon groups having asteroid structure. Steroid structures are well-known and suitably maycontain three six-membered rings and one five-membered ring fusedtogether as represented by the general formula:

Particularly preferred PAGs of the invention may comprise those of thefollowing Formulae (I) and (II):

wherein in each of Formulae (I) and (II):

M⁺ represent an organic onium salt, in particular aspects M⁺ is atrisubstituted sulfonium cation or disubstituted iodonium cation.

R₁ is a steroid structure;

m is an integer of 0 to 10 and preferably is a positive integer such asat least 1, 2, 3 or 4;

n is a positive integer suitably 1, 2, 3 or 4, more typically 1 or 2. M⁺is preferably photoactive.

As discussed above, in a preferred embodiment, PAGs of the inventioncomprise a sulfonate anion component where a chain that has at leastfour saturated non-cyclic atoms in interposed between (i) a sulfonicmoiety (SO₃ ⁻) and (ii) (a) a non-saturated moiety (e.g. phenyl or othercarbocyclic aryl), keto (carbonyl), ester and the like or (b) analicyclic group such as cyclohexyl, and the like. Exemplary anioncomponents may include those of the following formula:R(CH₂)n(CF₂)_(m)SO₃— where the sum of n and m is at least four, and R isother than a saturated, non-cyclic group (e.g. R may be ester, phenyl,cyclohexyl, etc.).

We have found that such a saturated chain can provide notably enhancedsolubility of the PAG compound in typical photoresist solvents such asethyl lactate, propylene glycol methyl ether acetate and the like.

Preferably, PAGs of the invention are used in positive-acting ornegative-acting chemically amplified photoresists, i.e. negative-actingresist compositions which undergo a photoacid-promoted crosslinkingreaction to render exposed regions of a coating layer of the resist lessdeveloper soluble than unexposed regions, and positive-acting resistcompositions which undergo a photoacid-promoted deprotection reaction ofacid labile groups of one or more composition components to renderexposed regions of a coating layer of the resist more soluble in anaqueous developer than unexposed regions. Ester groups that contain atertiary non-cyclic alkyl carbon or a tertiary alicyclic carboncovalently linked to the carboxyl oxygen of the ester are generallypreferred photoacid-labile groups of resins employed in photoresists ofthe invention. Acetal groups also are suitable photoacid-labile groups.

Preferred imaging wavelengths of photoresists of the invention includesub-300 nm wavelengths e.g. 248 nm, and sub-200 nm wavelengths e.g. 193nm and EUV.

Particularly preferred photoresists of the invention contain animaging-effective amount of one or more PAGs as disclosed herein and aresin that is selected from the group of:

1) a phenolic resin that contains acid-labile groups that can provide achemically amplified positive resist particularly suitable for imagingat 248 nm. Particularly preferred resins of this class include: i)polymers that contain polymerized units of a vinyl phenol and an alkylacrylate, where the polymerized alkyl acrylate units can undergo adeblocking reaction in the presence of photoacid. Exemplary alkylacrylates that can undergo a photoacid-induced deblocking reactioninclude e.g. t-butyl acrylate, t-butyl methacrylate, methyladamantylacrylate, methyl adamantyl methacrylate, and other non-cyclic alkyl andalicyclic acrylates that can undergo a photoacid-induced reaction, suchas polymers in U.S. Pat. Nos. 6,042,997 and 5,492,793, incorporatedherein by reference; ii) polymers that contain polymerized units of avinyl phenol, an optionally substituted vinyl phenyl (e.g. styrene) thatdoes not contain a hydroxy or carboxy ring substituent, and an alkylacrylate such as those deblocking groups described with polymers i)above, such as polymers described in U.S. Pat. No. 6,042,997,incorporated herein by reference; and iii) polymers that contain repeatunits that comprise an acetal or ketal moiety that will react withphotoacid, and optionally aromatic repeat units such as phenyl orphenolic groups.

2) a resin that is substantially or completely free of phenyl or otheraromatic groups that can provide a chemically amplified positive resistparticularly suitable for imaging at sub-200 nm wavelengths such as 193nm. Particularly preferred resins of this class include: i) polymersthat contain polymerized units of a non-aromatic cyclic olefin(endocyclic double bond) such as an optionally substituted norbornene,such as polymers described in U.S. Pat. No. 5,843,624 incorporatedherein by reference; ii) polymers that contain alkyl acrylate units suchas e.g. t-butyl acrylate, t-butyl methacrylate, methyladamantylacrylate, methyl adamantyl methacrylate, and other non-cyclic alkyl andalicyclic acrylates; such polymers have been described in U.S. Pat. No.6,057,083.

Resists of the invention also may comprise a mixture of distinct PAGs,typically a mixture of 2 or 3 different PAGs, more typically a mixturethat consists of a total of 2 distinct PAGs.

The invention also provide methods for forming relief images of thephotoresists of the invention, including methods for forming highlyresolved patterned photoresist images (e.g. a patterned line havingessentially vertical sidewalls) of sub-quarter micron dimensions orless, such as sub-0.2 or sub-0.1 micron dimensions.

The invention further provides articles of manufacture comprisingsubstrates such as a microelectronic wafer or a flat panel displaysubstrate having coated thereon the photoresists and relief images ofthe invention. Other aspects of the invention are disclosed infra.

In addition to compounds of Formulae I and II above, preferred PAGs ofthe invention include those of the following Formula (III):(R)—X—(C═O)O(CH₂)_(m)(CWY)_(n)SO₃M⁺  (III)

wherein R is a steroid structure,

X is a linker such as a chemical bond, C₁₋₁₀ carbon or hetero (e.g. N, Oor S) chain and the like;

W and Y are each independently in each occurrence hydrogen or fluoro,but where the carbon group directly adjacent to the SO₃ ⁻ preferably hasat least one fluoro atom and more preferably has at least two fluoroatoms (i.e. —CF₂—);

m, n and M+ are the same as defined for Formulae (I) and (II) above.

Yet additional preferred PAGs of the invention include those of thefollowing Formula (IV):(R)—X—O(C═O)(CH₂)_(m)(CWY)_(n)SO₃M⁺  (IV)

wherein R is a steroid structure,

X is a linker such as a chemical bond, C₁₋₁₀ carbon or hetero (e.g. N, Oor S) chain and the like;

W and Y are each independently in each occurrence hydrogen or fluoro,but where the carbon group directly adjacent to the SO₃ ⁻ preferably hasat least one fluoro atom and more preferably has at least two fluoroatoms (i.e. —CF₂—);

m, n and M+ are the same as defined for Formulae (I) and (II) above.

Generally PAGs of the invention include the following (in the belowstructures M+ is the same as defined above for Formulae (I) and (II),and the groups R, m and n are defined directly below the specifiedcompound):

Generally preferred onium salts of PAGs of the invention (includinggroups M⁺ in the above formulae) include sulfonium and iodonium saltphotoacid generators, such as those compounds disclosed in publishedEuropean application 0 708 368 A1. Such salts include those representedby the following formula:

where R₁ to R₅ each independently represents C1-16 optionallysubstituted alkyl group or a substituted or unsubstituted 1 carbocyclicaryl group such as phenyl, naphthyl, etc., or any two or more of R₁, R₂and R₃ may bond together to form a ring with the sulfur ring (e.g. a 5,6 or 7 membered ring with the sulfur atom). A preferred example of thecarbocyclic aryl group includes a C₆₋₁₄ monocyclic or a condensed ringaryl group. Preferred examples of the substituent on the aryl groupinclude an alkyl group, a haloalkyl group, a cycloalkyl group, an arylgroup, an alkoxy group, a nitro group, a carboxyl group, analkoxycarbonyl group, a hydroxyl group, mercapto group, and a halogenatom.

Specifically preferred PAGs of the invention include the following:

The following Scheme 1 exemplifies suitable approach for synthesis ofPAGs of the invention:

As stated herein above, various substituent groups of PAGs of theinvention may be optionally substituted. Substituted moieties aresuitably substituted at one or more available positions by, e.g.,halogen such as F, Cl Br and/or I, nitro, cyano, sulfono, alkylincluding C₁₋₁₆ alkyl with C₁₋₈ alkyl being preferred, haloalkyl such asfluoroalkyl (e.g. trifluoromethyl) and perhaloalkyl such asperfluoroC₁₋₄alkyl, alkoxy including C₁₋₁₆ alkoxy having one or moreoxygen linkages with C₁₋₈ alkoxy being preferred, alkenyl includingC₂₋₁₂ alkenyl with C₂₋₈ alkenyl being preferred, alkenyl including C₂₋₁₂alkenyl with C₂₋₈ alkynyl being preferred, aryl such as phenyl ornaphthyl and substituted aryl such as halo, alkoxy, alkenyl, alkynyland/or alkyl substituted aryl, preferably having the number of carbonatoms mentioned above for corresponding groups. Preferred substitutedaryl groups include substituted phenyl, anthracenyl and naphthyl.

As used herein, the term alkyl, alkenyl and alkynyl unless otherwisemodified refers to both cyclic and noncyclic groups, although of coursecyclic groups will comprise at least three carbon ring members. Alkenyland alkynyl groups of compounds of the invention have one or moreunsaturated linkages, typically 1 to about 3 or 4 unsaturated linkages.Also, the terms alkenyl and alkynyl as used herein refer to both cyclicand noncyclic groups, although straight or branched noncyclic groups aregenerally more preferred. Alkoxy groups of PAG compounds of theinvention have one or more oxygen linkages, typically 1 to about 5 or 6oxygen linkages. Alkylthio groups of PAGs of the invention have one ormore thioether linkages, typically 1 to about 5 or 6 thioether linkages.Alkylsulfinyl groups of PAG compounds of the invention have one or moresulfinyl (SO) linkages, typically 1 to about 5 or 6 sulfinyl linkages.Alkylsulfonyl groups of PAG compounds of the invention have one or moresulfonyl (SO₂) linkages, typically 1 to about 5 or 6 sulfonyl linkages.Preferred alkylamino groups of PAG compounds of the invention includethose groups having one or more primary, secondary and/or tertiary aminegroups, preferably 1 to about 3 or 4 amine groups. Suitable alkanoylgroups have one or more carbonyl groups, typically 1 to about 4 or 5carbonyl groups. Alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl,alkanoyl and other groups may be suitably either linear or branched.Carbocyclic aryl as used herein refers to non-hetero aromatic groupsthat have 1 to 3 separate or fused rings and 6 to about 18 carbon ringmembers and may include e.g. phenyl, naphthyl, biphenyl, acenaphthyl,phenanthracyl, and the like. Phenyl and naphthyl are often preferred.Suitable heteroaromatic or heteroaryl groups will have 1 to 3 rings, 3to 8 ring members in each ring and from 1 to about 3 hetero atoms (N, Oor S). Specifically suitable heteroaromatic or heteroaryl groups includee.g. courmarinyl, quinolinyl, pyridyl, pyrazinyl, pyrimdinyl, furyl,pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, indolyl,benzofuranyl, and benzothiazole.

As discussed above, PAGs of the invention are useful as the radiationsensitive component in photoresist compositions, including bothpositive-acting and negative-acting chemically amplified resistcompositions.

The photoresists of the invention typically comprise a resin binder anda photoactive component of the invention as described above. Preferablythe resin binder has functional groups that impart alkaline aqueousdevelopability to the resist composition. For example, preferred areresin binders that comprise polar functional groups such as hydroxyl orcarboxylate. Preferably the resin binder is used in a resist compositionin an amount sufficient to render the resist developable with an aqueousalkaline solution.

Preferably, a photoacid generator compound of the invention is employedin a chemically amplified positive-acting resist. A number of suchresist compositions have been described, e.g., in U.S. Pat. Nos.4,968,581; 4,883,740; 4,810,613 and 4,491,628 and Canadian PatentApplication 2,001,384, all of which are incorporated herein by referencefor their teaching of making and using chemically amplifiedpositive-acting resists. In accordance with the present invention, thoseprior resist compositions are modified by substitution of thephotoactive component of the invention as the radiation sensitivecomponent.

PAGs of the invention also are preferably used with polymers thatcontain one or more photoacid-labile groups and that are substantially,essentially or completely free of phenyl or other aromatic groups. Suchphotoresist compositions are particularly useful for imaging withsub-200 nm radiation such as 193 nm radiation.

For example, preferred polymers contain less than about 5 mole percentaromatic groups, more preferably less than about 1 or 2 mole percentaromatic groups, more preferably less than about 0.1, 0.02, 0.04 and0.08 mole percent aromatic groups and still more preferably less thanabout 0.01 mole percent aromatic groups. Particularly preferred polymersare completely free of aromatic groups. Aromatic groups can be highlyabsorbing of sub-200 nm radiation and thus are undesirable for polymersused in photoresists imaged with such short wavelength radiation.

Suitable polymers that are substantially or completely free of aromaticgroups and may be formulated with a PAG of the invention to provide aphotoresist for sub-200 nm imaging are disclosed in European applicationEP930542A1 of the Shipley Company.

Suitable polymers that are substantially or completely free of aromaticgroups suitably contain acrylate units such as photoacid-labile acrylateunits as may be provided by polymerization of methyladamanatylacrylate,methyladamanylmethacrylate, ethylfencylacrylate,ethylfencylmethacrylate, and the like; fused non-aromatic alicyclicgroups such as may be provided by polymerization of a norbornenecompound or other alicyclic compound having an endocyclic carbon-carbondouble bond; an anhydride such as may be provided by polymerization ofmaleic anhydride; and the like.

Preferred negative-acting compositions of the invention comprise amixture of materials that will cure, crosslink or harden upon exposureto acid, and a photoactive component of the invention.

Particularly preferred negative acting compositions comprise a resinbinder such as a phenolic resin, a crosslinker component and aphotoactive component of the invention. Such compositions and the usethereof has been disclosed in European Patent Applications 0164248 and0232972 and in U.S. Pat. No. 5,128,232 to Thackeray et al. Preferredphenolic resins for use as the resin binder component include novolaksand poly(vinylphenol)s such as those discussed above. Preferredcrosslinkers include amine-based materials, including melamine,glycolurils, benzoguanamine-based materials and urea-based materials.Melamine-formaldehyde resins are generally most preferred. Suchcrosslinkers are commercially available, e.g. the melamine resins soldby American Cyanamid under the trade names Cymel 300, 301 and 303.Glycoluril resins are sold by American Cyanamid under trade names Cymel1170, 1171, 1172, urea-based resins are sold under the trade names ofBeetle 60, 65 and 80, and benzoguanamine resins are sold under the tradenames Cymel 1123 and 1125.

Photoresists of the invention also may contain other materials. Forexample, other optional additives include actinic and contrast dyes,anti-striation agents, plasticizers, speed enhancers, sensitizers, etc.Such optional additives typically will be present in minor concentrationin a photoresist composition except for fillers and dyes which may bepresent in relatively large concentrations such as, e.g., in amounts offrom 5 to 30 percent by weight of the total weight of a resist's drycomponents.

A preferred optional additive of resists of the invention is an addedbase, particularly tetrabutylammonium hydroxide (TBAH), which canenhance resolution of a developed resist relief image. The added base issuitably used in relatively small amounts, e.g. about 1 to 10 percent byweight relative to the PAG, more typically 1 to about 5 weight percent.Other preferred basic additives include ammonium sulfonate salts such aspiperidinium p-toluenesulfonate and dicyclohexylammoniump-toluenesulfonate; alkyl amines such as tripropylamine anddodecylamine; aryl amines such as diphenylamine, triphenylamine,aminophenol, 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, etc.

The resin binder component of resists of the invention are typicallyused in an amount sufficient to render an exposed coating layer of theresist developable such as with an aqueous alkaline solution. Moreparticularly, a resin binder will suitably comprise 50 to about 90weight percent of total solids of the resist. The photoactive componentshould be present in an amount sufficient to enable generation of alatent image in a coating layer of the resist. More specifically, thephotoactive component will suitably be present in an amount of fromabout 1 to 40 weight percent of total solids of a resist. Typically,lesser amounts of the photoactive component will be suitable forchemically amplified resists.

The photoresists of the invention are generally prepared following knownprocedures with the exception that a PAG of the invention is substitutedfor prior photoactive compounds used in the formulation of suchphotoresists. For example, a resist of the invention can be prepared asa coating composition by dissolving the components of the photoresist ina suitable solvent such as, e.g., a glycol ether such as 2-methoxyethylether (diglyme), ethylene glycol monomethyl ether, propylene glycolmonomethyl ether; lactates such as ethyl lactate or methyl lactate, withethyl lactate being preferred; propionates, particularly methylpropionate and ethyl propionate; a Cellosolve ester such as methylCellosolve acetate; an aromatic hydrocarbon such toluene or xylene; or aketone such as methylethyl ketone, cyclohexanone and 2-heptanone.Typically the solids content of the photoresist varies between 5 and 35percent by weight of the total weight of the photoresist composition.

The photoresists of the invention can be used in accordance with knownprocedures. Though the photoresists of the invention may be applied as adry film, they are preferably applied on a substrate as a liquid coatingcomposition, dried by heating to remove solvent preferably until thecoating layer is tack free, exposed through a photomask to activatingradiation, optionally post-exposure baked to create or enhancesolubility differences between exposed and nonexposed regions of theresist coating layer, and then developed preferably with an aqueousalkaline developer to form a relief image. The substrate on which aresist of the invention is applied and processed suitably can be anysubstrate used in processes involving photoresists such as amicroelectronic wafer. For example, the substrate can be a silicon,silicon dioxide or aluminum-aluminum oxide microelectronic wafer.Gallium arsenide, ceramic, quartz or copper substrates may also beemployed. Substrates used for liquid crystal display and other flatpanel display applications are also suitably employed, e.g. glasssubstrates, indium tin oxide coated substrates and the like. A liquidcoating resist composition may be applied by any standard means such asspinning, dipping or roller coating. The exposure energy should besufficient to effectively activate the photoactive component of theradiation sensitive system to produce a patterned image in the resistcoating layer. Suitable exposure energies typically range from about 1to 300 mJ/cm². As discussed above, preferred exposure wavelengthsinclude sub-200 nm such as 193 nm. Suitable post-exposure baketemperatures are from about 50° C. or greater, more specifically fromabout 50 to 140° C. For an acid-hardening negative-acting resist, apost-development bake may be employed if desired at temperatures of fromabout 100 to 150° C. for several minutes or longer to further cure therelief image formed upon development. After development and anypost-development cure, the substrate surface bared by development maythen be selectively processed, for example chemically etching or platingsubstrate areas bared of photoresist in accordance with procedures knownin the art. Suitable etchants include a hydrofluoric acid etchingsolution and a plasma gas etch such as an oxygen plasma etch.

The following non-limiting example is illustrative of the invention.

EXAMPLE 1 Synthesis of TPS DHC TFBS

The three steps synthesis of TBPTMS 3OH-Ad TFBS is described in theScheme B. The details synthetic procedures for each step are outlinedbelow.

Step 1: Synthesis of DHC-TFBBr:

To a 3 L flask were added 120 g of Dehydrocholic acid (298.12 mmol),50.7 g of 1,1′-carbonyldiimidazole (CDI) and 1800 mL toluene under anitrogen sweep. The mixture was held at room temp for 2-3 hrs. Themixture was heated to reflux, then 70.40 g of4-bromo-3,3,4,4-tetrafluoro-butan-1-ol (312.9 mmol) was added over a 5min period. The mixture slowly becomes an amber colored solution withovernight heating. The reaction was cooled to 25 C, added to aseparatory funnel then washed with water (10×800 ml) until the pH wasequal to the pH of the DI water. To the top (amber colored) toluenelayer was added MgSO₄ and 15 g of activated charcoal. This mixture wasstirred for 2 hrs and then filtered. The filtrate (toluene) was removedunder reduced pressure resulting in a white solid. This solid was vacuumdried at 70 C for 18 hrs leaving 136 g of product (75% yield). Theproduct DHC-TFBBr was used in step 2.

Step 2: Synthesis of DHC-TFBSNa:

The product DHC-TFBBr (136 g) from step 1 was combined in a 3 L flaskwith 78 g sodium thiosufite, 56.8 g sodium bicarbonate, 1300 ml ofacetonitrile and 650 ml of deionized water. This mixture was held at 60C for 16 hrs. The mixture was cooled to room temp. The acetonitrilelayer was collected and placed in a 2 L flask and the water wasazeotroped off by removing ˜50% of the acetonitrile. Any salts whichprecipitated out were removed and the filtrate was poured into 10 L ofmethyl t-butyl ether. The solid was collected by filtration and dried.138.5 g of sulfinate salt was obtained which were added to a mixture of750 ml of acetonitrile and 350 ml of DI water. To the mixture was added150 mg of NaWO₄.2H₂O and 38.2 g of 30% hydrogen peroxide. The solutionwas stirred for 2-3 hrs at room temp. The product DHC-TFBSNa wasobtained after usual workup as colorless solid. Yield 100 g (71%). Theproduct was used in the 3rd step.

Step 3: Synthesis of TPS DHC-TFBS:

A mixture made of 111 g of DHC-TFBSNa, 60.50 g of triphenyl sulfoniumbromide in 750 ml methylene chloride and 100 ml of deionized water wasstirred at room temperature for 18 hours. The layers were separated andthe bottom organic layer was washed with 10×500 ml of deionized water.The methylene chloride was dried over MgSO₄ then reduced in volume by40%. The methylene chloride solution was slowly added to 10 L of Methylt-butyl ether. The solid was collected and dried leaving 139 g of TPSDHC-TFBS. The product was refluxed overnight in 500 ml of MTBE,collected and dried leaving 131 g of analytically pure product.

EXAMPLE 3 Photoresist Preparation and Lithographic Processing

A photoresist of the invention is prepared by mixing the followingcomponents with amounts expressed as weight percent based on totalweight of the resist compositions:

Resist components Amount (wt. %) Resin binder 15 Photoacid generator 4Ethyl lactate 81

The resin binder is a terpolymer (2-methyl-2-adamantylmethacrylate/beta-hydroxy-gamma-butyrolactonemethacrylate/cyano-norbornyl methacrylate. The photoacid generator isthe compound TPS DHC-TFBS, as prepared in Example 1 above. Those resinand PAG components are admixed in the ethyl lactate solvent.

The formulated resist composition is spin coated onto HMDS vapor primed4 inch silicon wafers and softbaked via a vacuum hotplate at 90° C. for60 seconds. The resist coating layer is exposed through a photomask at193 nm, and then the exposed coating layers are post-exposure baked at110° C. The coated wafers are then treated with 0.26N aqueoustetrabutylammonium hydroxide solution to develop the imaged resistlayer.

What is claimed is:
 1. A photoacid generator compound represented by astructure:

wherein M⁺ represents a cation group, and the definition of the group R,m and n are defined directly below the structure.
 2. A photoacidgenerator compound selected from:


3. A photoresist composition comprising a resin component and aphotoacid generator compound of claim
 1. 4. A photoresist compositioncomprising a resin component and a photoacid generator compound of claim2.
 5. A method for forming a photoresist relief image comprising: (a)applying a coating layer of a photoresist composition of claim 3 on asubstrate; (b) exposing the photoresist coating layer to patternedactivating radiation and developing the exposed photoresist layer toprovide a relief image.
 6. A method for forming a photoresist reliefimage comprising: (a) applying a coating layer of a photoresistcomposition of claim 4 on a substrate; (b) exposing the photoresistcoating layer to patterned activating radiation and developing theexposed photoresist layer to provide a relief image.